106 PROCEEDINGS OF THE ACADEMY OF [1895. 



river, although the beds found ou the Yegua are fossiliferous, and 

 those found farther west are reported to have yielded a very fair 

 number of that class of animal life. Plant remains are numerous, 

 both in the form of silicified and lignitized wood, and leaves of many 

 kinds are extremely abundant. None of these have yet been 

 studied, but from the fact that silicified palm wood occurs, although 

 sparingly, among the upper gray sands, the climate was slightly 

 warmer than at present. 



The general conditions of deposition during this period appear to 

 have been those of a marsh subject to periodical deep, wide-spread 

 inundation and a gradual, though slow, subsidence. The Marine 

 beds lying to the north evidently stood at a much higher relative 

 elevation than at present. Their southern boundary is everywhere 

 carved into bold outlines and deeply indented bays showing at places 

 steepsided and shelving bluffs where the Yegua clays rest uncon- 

 formably upon and against them, and from which boulders of fossil- 

 iferous sandstones have fallen and are now found in considerable 

 ]] umbers imbeded in the sands and lying between one and two 

 miles from the line of contact. At other places where bay- like con- 

 ditions prevailed, the placid waters of the flooded areas favored a 

 calmer deposition and growth of plant life ; the lines of contact are 

 not so far apart in their general conditions and range of dip. 



Instances of the former conditions are many. Typical illustra- 

 tions of this bluff-like shore line may be seen at Cook's Mountain, 

 in Houston County, and near Elm Creek, north of Bryan, in 

 Brazos County. At Cook's Mountain the hill rises almost abruptly 

 from the level of Milam branch to an elevation of 130 feet above 

 the stream bed, and is capped with fifty feet of altered glauconitic 

 fossiliferous sandstone. The gypseous clays of the Yegua stage are 

 found only on the south side of the stream, and rest upon a heavy 

 bed of fossiliferous sand projecting from the side of the mountain. 

 The Brazos section also shows this want of conformity in quite as 

 strong a manner. The Marine beds occur capping the higher hills 

 ten miles north of College Station and lying at an elevation of 375 

 feet, while College Station has an altitude of 350 feet. The dip of 

 the Marine beds in this section closely approaches 75 feet per mile 

 and these beds, after allowing for the difference of elevation, should 

 have been found at 725-750 feet in the well bored at the college, 

 flie bore, however, was over 900 feet deep before fossils occurred, 



